What is the recommended evaluation and management for a patient presenting with bronchitis, including how to differentiate acute viral bronchitis from chronic bronchitis associated with chronic obstructive pulmonary disease?

Evaluation and Management of Bronchitis

Acute bronchitis is a clinical diagnosis made when an adult presents with predominant acute cough lasting less than 3 weeks, with or without sputum production, after ruling out pneumonia, the common cold, acute asthma, and COPD exacerbation. 1, 2

Differentiating Acute Viral Bronchitis from Chronic Bronchitis/COPD

Acute Bronchitis Definition

• Acute bronchitis is characterized by sudden onset of cough lasting less than 3 weeks, typically caused by viral infection (>90% of cases), without evidence of pneumonia or chronic lung disease. 1, 3
• The condition is self-limited, with cough typically resolving in 10-14 days but may persist up to 3 weeks. 2, 3

Chronic Bronchitis Definition

• Chronic bronchitis is defined as cough with excessive mucus production on most days during 3 consecutive months for more than 2 successive years. 1
• This condition results from prolonged exposure to pulmonary irritants, most commonly cigarette smoke, and is associated with irreversible reduction in maximal airflow velocity. 1, 4
• Patients have underlying obstructive pulmonary disease and often experience acute exacerbations superimposed on their chronic condition. 1

Clinical Evaluation for Acute Bronchitis

Rule Out Pneumonia First

The primary goal is excluding pneumonia, which requires specific treatment and has significant morbidity if missed. 1, 2

Assess these four clinical findings: 1, 2

• Heart rate >100 beats/min
• Respiratory rate >24 breaths/min
• Oral temperature >38°C
• Focal chest examination findings (rales, egophony, fremitus)

If all four findings are absent in otherwise healthy adults under 70 years without comorbidities, pneumonia likelihood is sufficiently low that chest radiograph is not required. 1, 2

If any finding is present, obtain a chest radiograph to rule out pneumonia. 1, 2

Rule Out Asthma

• Approximately 33% of patients initially diagnosed with acute bronchitis actually have undiagnosed asthma. 1, 2
• In patients with ≥2 similar "bronchitis" episodes in the prior 5 years, 65% have mild asthma. 1, 2

Suspect asthma when: 2

• Recurrent episodes of similar symptoms
• Wheezing present
• Nocturnal cough or symptoms worsening with cold air/exercise
• Symptoms persist beyond 3 weeks

Important caveat: Transient bronchial hyperresponsiveness occurs in 40% of patients with acute viral bronchitis and typically resolves within 2-3 weeks (occasionally up to 2 months), so asthma should not be diagnosed during the acute phase unless severe airflow obstruction is present. 1, 2

Rule Out COPD Exacerbation

• Patients with known COPD who develop acute cough have a COPD exacerbation, not acute bronchitis, and require different management. 2
• Acute exacerbation of chronic bronchitis (AECB) is characterized by unstable lung function with worsening airflow and symptoms in patients with established chronic bronchitis. 4

Distinguish from Common Cold

• The common cold presents primarily with upper respiratory symptoms (rhinorrhea, nasal congestion, sore throat) with cough as a secondary feature. 1, 2
• Acute bronchitis is diagnosed when cough is the predominant symptom, regardless of upper respiratory prodrome. 2

Critical Diagnostic Pitfalls

Purulent Sputum Does NOT Indicate Bacterial Infection

Green or yellow sputum occurs in 89-95% of viral bronchitis cases and does not indicate bacterial infection or need for antibiotics. 2

• Sputum discoloration reflects inflammatory cells and sloughed epithelium, not bacterial presence. 1, 2
• Purulent sputum does not reliably differentiate bacterial from viral infection. 1

Routine Testing is NOT Indicated

• Viral cultures, serologic assays, sputum analyses, and inflammatory markers should not be routinely performed for acute bronchitis diagnosis. 1, 2
• These tests rarely identify the responsible organism in clinical practice. 1

Management of Acute Bronchitis

Antibiotics Are NOT Recommended

Antibiotics do not contribute to overall improvement in acute bronchitis; they shorten cough by only ~0.5 days while exposing patients to adverse effects. 2, 3

• More than 90% of acute bronchitis cases are viral. 3, 5
• Antibiotics should only be considered if pertussis is suspected or the patient is at high risk for pneumonia (age ≥65 years). 5

Symptomatic Treatment

• Patient education regarding expected cough duration (2-3 weeks) is the cornerstone of management. 3, 2
• Evidence does not support antitussives, honey, antihistamines, anticholinergics, oral NSAIDs, or inhaled/oral corticosteroids. 3
• Strategies to reduce antibiotic prescribing include describing acute bronchitis as a "chest cold" and offering delayed prescriptions. 3

Management of Acute Exacerbation of Chronic Bronchitis (AECB)

When to Treat with Antibiotics

Antibacterial treatment should be reserved for patients with at least 1 key symptom AND 1 risk factor. 4

Key symptoms (need ≥1): 4

• Increased dyspnea
• Increased sputum production
• Increased sputum purulence

Risk factors (need ≥1): 4

• Age ≥65 years
• FEV₁ <50% predicted
• ≥4 exacerbations in 12 months
• One or more comorbidities

Antibiotic Selection for AECB

For moderate severity exacerbation: 4

• Newer macrolide, extended-spectrum cephalosporin, or doxycycline

For severe exacerbation: 4

• High-dose amoxicillin/clavulanate or respiratory fluoroquinolone

Bacterial Pathogens in AECB

• The three most prevalent pathogens are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. 1, 4, 6
• These organisms can colonize airways in stable chronic bronchitis, making interpretation of sputum cultures challenging. 1
• Pseudomonas aeruginosa is increasingly prevalent in patients with severe underlying disease. 6

Supportive Care for AECB

All AECB patients should receive: 4

• Removal of irritants (smoking cessation)
• Bronchodilator therapy
• Oxygen if indicated
• Hydration
• Systemic corticosteroids when appropriate
• Chest physical therapy

Evaluation of Persistent Cough (>3 Weeks)

When cough persists beyond 3 weeks, acute bronchitis is no longer the diagnosis and systematic evaluation for other causes is required. 1, 2

Consider: 2, 7

• Post-infectious cough (though this should resolve by 8 weeks)
• Upper airway cough syndrome (postnasal drip)
• Asthma or cough-variant asthma
• Gastroesophageal reflux disease
• Pertussis (if paroxysmal cough, post-tussive vomiting, or inspiratory whoop present)